Reiko Heckel and Alexey Cherchago: Structural and Behavioural Compatibility of Graphical Service Specifications. In Logic and Algebraic Programming, vol. 70, no. 1, pp. 15--33 (2007)
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@article{Heckel2007, author = {Reiko Heckel and Alexey Cherchago}, title = {Structural and Behavioural Compatibility of Graphical Service Specifications}, journal = {Logic and Algebraic Programming}, year = {2007}, volume = {70}, number = {1}, pages = {15--33}, month = {January} }

The ability of applications to dynamically discover required services is a key motivation for Web Services. However, this aspect is not entirely supported by current Web Services standards. It is our objective to develop a formal approach, allowing the automation of the discovery process. The approach is based on the matching of interface specifications of the required and provided services. In the present paper, we establish an integral notion of structural and behavioural compatibility of service specifications. While structural information is represented by operation declarations, behavioural descriptions are provided by contracts expressed as graph transformation rules with positive and negative application conditions. The integration of structural and behavioural descriptions is facilitated by typed and parameterised graph transformation systems, augmenting the rule-based description of behaviour by a type graph and operation declarations representing the structural aspect. The matching relation taking into account this combination is called parameterised substitution morphism. We show that substitution morphisms satisfy the semantic requirement inherent in its name: the substitutability of abstract operations by (calls to) concrete ones.

Alexey Cherchago and V. Finaev: Formalization of the development process for a software-hardware reflexodiagnostic tool. In Scientific bulletin of Academy of Information Technologies in Education, Science and Balneology, vol. 3 (1999)
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@article{Cherchago1999, author = {Alexey Cherchago and V. Finaev}, title = {Formalization of the development process for a software-hardware reflexodiagnostic tool}, journal = {Scientific bulletin of Academy of Information Technologies in Education, Science and Balneology}, year = {1999}, volume = {3} }

Alexey Cherchago and Reiko Heckel: Specification Matching of Web Services Using Conditional Graph Transformation Rules. In Proceedings of the conference on Graph Transformation (ICGT 2004), Rome (Italy). Springer (Berlin/Heidelberg), LNCS, vol. 3256 / 2004, pp. 304--318 (2004) Graph Transformations
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@inproceedings{Cherchago2004, author = {Alexey Cherchago and Reiko Heckel}, title = {Specification Matching of Web Services Using Conditional Graph Transformation Rules}, booktitle = {Proceedings of the conference on Graph Transformation (ICGT 2004), Rome (Italy)}, year = {2004}, volume = {3256 / 2004}, series = {LNCS}, pages = {304--318}, address = {Berlin/Heidelberg}, publisher = {Springer}, note = {Graph Transformations} }

The ability of applications to dynamically discover required services is a key problem for Web Services. However, this aspect is not adequately supported by current Web Services standards. It is our objective to develop a formal approach allowing the automation of the discovery process. The approach is based on the matching of requestors requirements for a useful service against service descriptions. In the present paper, we concentrate on behavioral compatibility. This amounts to check a relation between provided and required operations described via operation contracts. Graph transformation rules with positive and negative application conditions are proposed as a visual formal notation for contract specification. We establish the desired semantic relation between requestor and provider and prove the soundness and completeness of a syntactic notion of matching w.r.t. this relation.

Reiko Heckel and Alexey Cherchago: Application of Graph Transformation for Automating Web Service Discovery. In Proceedings of the seminar on Language Engineering for Model-Driven Software Development (2003), Dagstuhl (Germany). Internationales Begegnungs- und Forschungszentrum für Informatik (IBFI) (Dagstuhl, Germany), Dagstuhl Seminar Proceedings (2004)
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@inproceedings{Heckel2004c, author = {Reiko Heckel and Alexey Cherchago}, title = {Application of Graph Transformation for Automating Web Service Discovery}, booktitle = {Proceedings of the seminar on Language Engineering for Model-Driven Software Development (2003), Dagstuhl (Germany)}, year = {2004}, series = {Dagstuhl Seminar Proceedings}, address = {Dagstuhl, Germany}, month = {March}, publisher = {Internationales Begegnungs- und Forschungszentrum für Informatik (IBFI)} }

The paper represents current achievements of an ongoing research that aims to develop a formal approach supporting an automatic selection of a Web service sought by a requestor. The approach is based on the matching the requestor’s requirements for a "useful" service against the service description offered by the provider. We focus on the checking behavioral compatibility between operation contracts specifying pre-conditions and effects of required and provided operations. Graph transformation rules with positive application conditions are proposed as a visual formal notation for contracts. The desired dependence between requestor and provider contracts is determined by the semantic compatibility relation and syntactic matching procedure that is sound w.r.t. this relation.

Alexey Cherchago: Formal Semantics for a UML fragment using UML/OCL metamodeling. In Proceedings of the 6th IASTED International Conference on Software Engineering and Applications (SEA 2002), Cambridge, MA (USA). ACTA Press (2002)
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@inproceedings{Tchertchago2002, author = {Alexey Cherchago}, title = {Formal Semantics for a UML fragment using UML/OCL metamodeling}, booktitle = {Proceedings of the 6th IASTED International Conference on Software Engineering and Applications (SEA 2002), Cambridge, MA (USA)}, year = {2002}, publisher = {ACTA Press} }

This paper studies the definition of formal semantics for a fragment of the Unified Modeling Language (UML) that covers some static and dynamic UML concepts. The idea of the considered methodological approach is based on the formalization of an information system in order to use this model as a semantic reference structure. Metamodels for abstract syntax and a set of constraints for static semantics of metaclasses are provided for this fragment. The development of an integrated model enables to incorporate metamodels for class and statechart diagrams with semantic reference model and, thus, to determine semantic relationship between them. We use the Object Constraint Language (OCL) as an expression language to describe a set of well-formedness rules and semantic constraints for considered models. Practical experiments with the USE tool are carried out to analyse and justify constraints.

Alexey Cherchago and N. Alexandrova: A Model of a Physician’s Decision-Making Process using Electropunctural Methods of Diagnostics. In Proceedings of the All-Russia Students, Young Scientists and Specialists Scientific and Technical Conference on Biotechnical, Medical and Environmental Systems and Complexes (Ryazan, Russia). (2000)
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@inproceedings{Cherchago00, author = {Alexey Cherchago and N. Alexandrova}, title = {A Model of a Physician’s Decision-Making Process using Electropunctural Methods of Diagnostics}, booktitle = {Proceedings of the All-Russia Students, Young Scientists and Specialists Scientific and Technical Conference on Biotechnical, Medical and Environmental Systems and Complexes (Ryazan, Russia)}, year = {2000} }

Alexey Cherchago: Application of the Structured Analysis and Design Technique (SADT) Methodology for the Medical Information Systems Development. In Proceedings of the All-Russia Students’, Young Scientists’ and Specialists’ Scientific and Technical Conference "New Information Technologies in Scientific Researches and in Education" (Ryazan, Russia). (1999)
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@inproceedings{Cherchago99, author = {Alexey Cherchago}, title = {Application of the Structured Analysis and Design Technique (SADT) Methodology for the Medical Information Systems Development}, booktitle = {Proceedings of the All-Russia Students’, Young Scientists’ and Specialists’ Scientific and Technical Conference "New Information Technologies in Scientific Researches and in Education" (Ryazan, Russia)}, year = {1999} }

Alexey Cherchago: A generalized schema of a decision-making process of a SCENAR-therapeutist. In Proceedings of the Scientific and Technical Conference on Medical Information Systems (MIS 1998), Taganrog (Russia). (1998)
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@inproceedings{Cherchago98, author = {Alexey Cherchago}, title = {A generalized schema of a decision-making process of a SCENAR-therapeutist}, booktitle = {Proceedings of the Scientific and Technical Conference on Medical Information Systems (MIS 1998), Taganrog (Russia)}, year = {1998} }

Alexey Cherchago and Gregor Engels: Preservation of Compatibility under Evolution of Software Components. In International ERCIM-ESF Workshop on Challenges in Software Evolution (ChaSE 2005), Berne (Switzerland). (2005)
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@inproceedings{Chrechago2005, author = {Alexey Cherchago and Gregor Engels}, title = {Preservation of Compatibility under Evolution of Software Components}, booktitle = {International ERCIM-ESF Workshop on Challenges in Software Evolution (ChaSE 2005), Berne (Switzerland)}, year = {2005}, month = {April} }

Reiko Heckel and Alexey Cherchago and Marc Lohmann: A Formal Approach to Service Specification and Matching based on Graph Transformation. In Proceedings of the First International Workshop on Web Services and Formal Methods (WSFM 2004), Pisa, Italy. Elsevier, vol. 105, pp. 37--49 (2004)
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@inproceedings{Heckel2004b, author = {Reiko Heckel and Alexey Cherchago and Marc Lohmann}, title = {A Formal Approach to Service Specification and Matching based on Graph Transformation}, booktitle = {Proceedings of the First International Workshop on Web Services and Formal Methods (WSFM 2004), Pisa, Italy}, year = {2004}, volume = {105}, pages = {37--49}, month = {December }, publisher = {Elsevier} }

When Web services are composed by linking service providers and requestors, the requestor's requirements for a "useful" service have to be matched against the service description offered by the provider. Among other things, service specifications (requirements or descriptions) may contain operation contracts specifying pre-conditions and effects of (required or provided) operations. In this paper we provide a semi-formal, UML-based notation for contracts and contract matching, as well as a formalization of these notions in terms of graph transformation. We establish the desired semantic relation between requestor and provider specifications and prove the soundness of our syntactic notion of matching w.r.t. this relation.

Gregor Engels and Reiko Heckel and Alexey Cherchago: Flexible Interconnection of Graph Transformation Modules - A Systematic Approach. In H.-J. Kreowski, U. Montanari, F. Orejas, G. Rozenberg, G. Taentzer (eds.): Formal Methods in Software and System Modeling. Essays Dedicated to Hartmut Ehrig on the Occasion of His 60th Birthday. LNCS, , vol. 3393, pp. 38--63 Springer (Berlin/Heidelberg) (2005)
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@incollection{Engels2005a, author = {Gregor Engels and Reiko Heckel and Alexey Cherchago}, title = {Flexible Interconnection of Graph Transformation Modules - A Systematic Approach}, booktitle = {Formal Methods in Software and System Modeling. Essays Dedicated to Hartmut Ehrig on the Occasion of His 60th Birthday}, publisher = {Springer}, year = {2005}, volume = {3393}, series = {LNCS}, pages = {38--63}, address = {Berlin/Heidelberg} }

Modularization is a well-known concept to structure software systems as well as their specifications. Modules are equipped with export and import interfaces and thus can be connected with other modules requesting or providing certain features. In this paper, we study modules the interfaces of which consist of behavioral specifications given by typed graph transformation systems. We introduce a framework for classifying and systematically defining relations between typed graph transformation systems. The framework comprises a number of standard ingredients, like homomorphisms between type graphs and mappings between sets of graph transformation rules. The framework is applied to develop a novel concept of substitution morphism by separating preconditions and effects in the specification of rules. This substitution morphism is suited to define the semantic relation between export and import interfaces of requesting and providing modules.

Alexey Cherchago: Service Specification and Matching Based on Graph Transformation. Type: Phd Thesis (2006)
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@phdthesis{Cherchago2006, author = {Alexey Cherchago}, title = {Service Specification and Matching Based on Graph Transformation}, year = {2006} }

One of the main tasks of modern application integration projects is to allow one business unit (requestor) to use services offered by another business unit (provider). When software systems of business partners are composed, an import interface of the requestor system is connected to an exportinterface of the provider system. Here, the import interface specification containing the requestor's requirements for a needed service has to be matched against the export interface specification describing the provided service. Usually, software engineers carry out matching of interface specifications manually; it makes the design and implementation of composite software expensive and error-prone. Therefore, the demand for instruments that would automate the matching procedure is high. In this thesis, we develop a new technique facilitating integration of software systems. To this end, we solve a problem of how to construct visual and formal interface specifications comprising semantic descriptions. Our method also includes a matching procedure that checks compatibility of such specifications. Interface specifications consist of structural and behavioural compartments. The structural compartment, given by a signature analogous to those appearing in algebraic specifications, defines operation declarations. The behavioural compartment, modelled by a conditional graph transformation system (GTS), contains operation contracts in the form of graph transformation rules. The rules of conditional GTS are equipped with loose semantics to describe operations in the import interface, and with strict semantics to describe those in the export interface. Composition of two compartments leads to an integral interface specification which is represented by the novel concept of parameterized conditional GTS. We develop three kinds of compatibility relations underlying the matching procedure. The intended correspondence between declarations and contracts of the required and provided operations is reflected by structural and behavioural compatibility relations that are established over the corresponding compartments of interface specifications. These two compatibility relations are combined into an integral compatibility relation that links the integral specification of the import interface to the one of the export interface. Furthermore, the constructed relations are equipped with rigorously formulated semantic requirements to compatibility and are justified against them. The introduced mathematical theory is supplemented with a conceptual framework. It is aimed at generating interface specifications that are suitable for automation of the matching process. The framework is based on an industry standard that outlines a uniform way of generating specifications. We use the standard issued by the Open Travel Alliance (OTA) in our example scenario where we develop and match standard-based interface specifications of Web services taken from the travelling business domain. Compatibility of interface specifications is necessary but not sufficient for accurate interactions between systems. The integration process is based on the assumption that these systems are correct. First and foremost, this correctness means that interface specifications representing externally visible parts of systems are consistent with implementations which appear internally in the systems. To check this assumption, we propose a model describing external as well as internal parts of a system. The model, formally represented by a graph transformation module, defines consistency relations between external and internal specifications and allows to validate correctness of systems prior to the integration. The proposed model and the matching procedure developed in the thesis are the key elements of a technology designed to improve the application integration process, making it theoretically well-defined and practically machine-processable.

Alexey Cherchago: Analysis of the Metamodeling Semantics for OCL. Type: Master Thesis (2002)
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@mastersthesis{Cherchago2002, author = {Alexey Cherchago}, title = {Analysis of the Metamodeling Semantics for OCL}, year = {2002} }

Alexey Cherchago and Andrej Yaroshevski: Device to Diagnose the Patient State via Characteristics of the Biological Active Points. Patent 2211660 (2003) Patent 2211660
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@misc{Cherchago2003, author = {Alexey Cherchago and Andrej Yaroshevski}, title = {Device to Diagnose the Patient State via Characteristics of the Biological Active Points}, howpublished = {Patent 2211660}, month = {September}, year = {2003}, note = {Patent 2211660} }